What is the preferred IM injection site for children under 3 years of age?

The preferred intramuscular (IM) injection site for children under 3 years of age is the vastus lateralis muscle. This site is located in the outer thigh and is particularly suitable for young children because it is large enough to accommodate the volume of medication needed and has a lower risk of injury to nerves and blood vessels compared to other sites.

In infants and toddlers, muscle mass in the deltoid is insufficient for safe and effective IM injections. The dorsogluteal site, while used in older children and adults, has associated risks such as hitting the sciatic nerve and is thus not recommended for young children. The quadriceps muscle could technically be used, but it is not a standard recommendation as the vastus lateralis provides a safer and more accessible site for administering vaccines and other medications.

Overall, the vastus lateralis is chosen for its size, accessibility, and safety, making it the optimal injection site for this age group.